In recent years, efforts toward the development of flexible displays have been made in full swing. These displays require films that substitute for glass to reduce their weight and prevent cracking due to bending or impact. In particular, as a material to substitute for glass used for the front faces of touch panels, there are increasing demands for films having surfaces that are resistant to scratching, specifically, with a pencil hardness of 5H or higher. It is necessary for such a film to have not only a high transparency, but also a high bending resistance, which is in a trade-off relationship with the above-mentioned surface hardness.
As techniques for improving the surface hardness, Japanese Unexamined Patent Publication (Kokai) No. 2014-65172, Japanese Unexamined Patent Publication (Kokai) No. 2014-134674, Japanese Unexamined Patent Publication (Kokai) No. 2014-210412 and Japanese Unexamined Patent Publication (Kokai) No. HEI 8-15682 have proposed high hardness films having hard coat layers on film layers of acrylic resin, polyester resin, triacetyl cellulose resin or the like. However, they have the problem of deterioration in bending resistance because an increase in the total film thickness is necessary to realize a high surface hardness. Japanese Unexamined Patent Publication (Kokai) No. 2009-198811, Japanese Unexamined Patent Publication (Kokai) No. 2007-147798 and Japanese Unexamined Patent Publication (Kokai) No. 2006-178123 have proposed thin films having high hardness. However, a sufficiently high bending resistance cannot be maintained as the bending curvature decreases. In addition, Japanese Unexamined Patent Publication (Kokai) No. 2005-15790 describes a fully aromatic polyamide film. That film has high bending resistance, but it cannot realize a sufficiently high surface hardness when used in the form of a single film layer.
It could therefore be helpful to provide a laminated film that has a high surface hardness even when being thin to ensure the simultaneous realization of a high surface hardness and a high bending resistance.